| 1 | Psychiatr. Genet. 2005 Mar 15: 37-44 |
|---|---|
| PMID | 15722956 |
| Title | Candidate psychiatric illness genes identified in patients with pericentric inversions of chromosome 18. |
| Abstract | Both the long and short arms of chromosome 18 have been consistently identified as potential locations for schizophrenia and bipolar affective disorder susceptibility genes. We previously described the identification of two independent pericentric inversions of chromosome 18 [inv(18)(p11.31;q21.2) and inv(18)(p11.31;q21.1)] occurring in two small families in which carriers have been diagnosed with schizophrenia and bipolar affective disorder, respectively. Using fluorescence in situ hybridization on patient metaphase chromosomes we have identified the locations of all four chromosome breakpoints in the inversion carriers. Neither pericentric inversion results in a direct gene disruption. However, each inversion breakpoint has the potential to perturb local gene expression by position effect or by the separation of important regulatory (enhancer) sequences from the core gene sequences. Five genes in the localities of the breakpoints have been identified as good candidates for the genetic basis of psychiatric illness in these families; TTMA, a novel membrane spanning protein; TCF4, a basic helix-loop-helix transcription factor; DLGAP1, an interactor of the PSD-95 synaptic protein; and ARKL1 and ARKL2, novel members of the ubiquitin ligase gene family. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 2 | Nature 2009 Aug 460: 744-7 |
| PMID | 19571808 |
| Title | Common variants conferring risk of schizophrenia. |
| Abstract | schizophrenia is a complex disorder, caused by both genetic and environmental factors and their interactions. Research on pathogenesis has traditionally focused on neurotransmitter systems in the brain, particularly those involving dopamine. schizophrenia has been considered a separate disease for over a century, but in the absence of clear biological markers, diagnosis has historically been based on signs and symptoms. A fundamental message emerging from genome-wide association studies of copy number variations (CNVs) associated with the disease is that its genetic basis does not necessarily conform to classical nosological disease boundaries. Certain CNVs confer not only high relative risk of schizophrenia but also of other psychiatric disorders. The structural variations associated with schizophrenia can involve several genes and the phenotypic syndromes, or the 'genomic disorders', have not yet been characterized. Single nucleotide polymorphism (SNP)-based genome-wide association studies with the potential to implicate individual genes in complex diseases may reveal underlying biological pathways. Here we combined SNP data from several large genome-wide scans and followed up the most significant association signals. We found significant association with several markers spanning the major histocompatibility complex (MHC) region on chromosome 6p21.3-22.1, a marker located upstream of the neurogranin gene (NRGN) on 11q24.2 and a marker in intron four of transcription factor 4 (TCF4) on 18q21.2. Our findings implicating the MHC region are consistent with an immune component to schizophrenia risk, whereas the association with NRGN and TCF4 points to perturbation of pathways involved in brain development, memory and cognition. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 3 | Curr. Opin. Neurobiol. 2010 Dec 20: 810-5 |
| PMID | 20934321 |
| Title | The neurobiology of schizophrenia: new leads and avenues for treatment. |
| Abstract | Recent large-scale genetic studies have provided robust evidence implicating several novel susceptibility genes for schizophrenia. These include ZNF804A, TCF4 and NRGN, which contain common variants that weakly increase schizophrenia susceptibility, and NRXN1, in which rare copy number variants have a greater impact on schizophrenia risk. Investigation of these and other substantiated susceptibility genes are providing valuable insight into the primary neurobiological mechanisms underlying schizophrenia, which may lead to novel therapeutic interventions for the disorder. In the meantime, several novel pharmacological strategies, including activation of mGluRs, elevation of synaptic glycine and inhibition of phosphodiesterase 10A, have recently shown promise for the treatment of schizophrenia in clinical trials. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 4 | Biol. Psychiatry 2010 Oct 68: 671-3 |
| PMID | 20673877 |
| Title | Common variants in major histocompatibility complex region and TCF4 gene are significantly associated with schizophrenia in Han Chinese. |
| Abstract | schizophrenia is a complex major psychiatric disorder affecting ?1% of the world population. Recently, in a genome-wide association study and a follow-up in Caucasians, Stefansson et al. examined 7662 schizophrenic cases and 29053 normal control subjects and reported seven common single nucleotide polymorphisms (SNPs) that were significantly (>10(-8)) associated with schizophrenia. To investigate whether these risk SNPs were significantly associated in Han Chinese, we analyzed the seven SNPs in 2496 schizophrenia patients and 5184 normal control subjects. Because only three of the seven SNPs were polymorphic in Han Chinese, we genotyped two additional common SNPs from the same risk regions. Three SNPs, rs6932590 (p = .00096), rs3131296 (p = 1.29 × 10(-6)), and rs3130375 (p = 1.76 × 10(-5)), mapping to the major histocompatibility complex region and one SNP rs2958182 (p = 3.64 × 10(-6)) located in the TCF4 gene were significant in our sample set. A meta-analysis using published genome-wide association study results also supported our findings. Our results confirm that common risk factors in the major histocompatibility complex region and TCF4 gene are associated with schizophrenia in Han Chinese, but our results fail to show an association with SNP rs12807809 in the NRGN gene. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 5 | Biol. Psychiatry 2010 Oct 68: 671-3 |
| PMID | 20673877 |
| Title | Common variants in major histocompatibility complex region and TCF4 gene are significantly associated with schizophrenia in Han Chinese. |
| Abstract | schizophrenia is a complex major psychiatric disorder affecting ?1% of the world population. Recently, in a genome-wide association study and a follow-up in Caucasians, Stefansson et al. examined 7662 schizophrenic cases and 29053 normal control subjects and reported seven common single nucleotide polymorphisms (SNPs) that were significantly (>10(-8)) associated with schizophrenia. To investigate whether these risk SNPs were significantly associated in Han Chinese, we analyzed the seven SNPs in 2496 schizophrenia patients and 5184 normal control subjects. Because only three of the seven SNPs were polymorphic in Han Chinese, we genotyped two additional common SNPs from the same risk regions. Three SNPs, rs6932590 (p = .00096), rs3131296 (p = 1.29 × 10(-6)), and rs3130375 (p = 1.76 × 10(-5)), mapping to the major histocompatibility complex region and one SNP rs2958182 (p = 3.64 × 10(-6)) located in the TCF4 gene were significant in our sample set. A meta-analysis using published genome-wide association study results also supported our findings. Our results confirm that common risk factors in the major histocompatibility complex region and TCF4 gene are associated with schizophrenia in Han Chinese, but our results fail to show an association with SNP rs12807809 in the NRGN gene. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 6 | Front Behav Neurosci 2010 -1 4: 23 |
| PMID | 20485477 |
| Title | New Genetic Findings in Schizophrenia: Is there Still Room for the Dopamine Hypothesis of Schizophrenia? |
| Abstract | schizophrenia is a highly heritable disorder, but the identification of specific genes has proven to be a difficult endeavor. Genes involved in the dopaminergic system are considered to be major candidates since the "dopamine hypothesis" of impairment in dopaminergic neurotransmission is one of the most widely accepted hypotheses of the etiology of schizophrenia. The overall findings from candidate studies do provide some support for the "dopamine hypothesis." However, results from the first systematic genome-wide association (GWA) studies have implicated variants within ZNF804A, NRGN, TCF4, and variants in the MHC region on chromosome 6p22.1. Although these genes may not immediately impact on dopaminergic neurotransmission, it remains possible that downstream impairments in dopaminergic function are caused. Furthermore, only a very small fraction of all truly associated genetic variants have been detected and many more associated variants will be identified in the future by GWA studies and alternative approaches. The results of these studies may allow a more comprehensive re-evaluation of the dopamine hypothesis. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 7 | Hum. Mol. Genet. 2010 Jul 19: 2841-57 |
| PMID | 20457675 |
| Title | SMARCA2 and other genome-wide supported schizophrenia-associated genes: regulation by REST/NRSF, network organization and primate-specific evolution. |
| Abstract | The SMARCA2 gene, which encodes BRM in the SWI/SNF chromatin-remodeling complex, was recently identified as being associated with schizophrenia (SZ) in a genome-wide approach. Polymorphisms in SMARCA2, associated with the disease, produce changes in the expression of the gene and/or in the encoded amino acid sequence. We show here that an SWI/SNF-centered network including the Smarca2 gene is modified by the down-regulation of REST/NRSF in a mouse neuronal cell line. REST/NRSF down-regulation also modifies the levels of Smarce1, Smarcd3 and SWI/SNF interactors (Hdac1, RcoR1 and Mecp2). Smarca2 down-regulation generates an abnormal dendritic spine morphology that is an intermediate phenotype of SZ. We further found that 8 (CSF2RA, HIST1H2BJ, NOTCH4, NRGN, SHOX, SMARCA2, TCF4 and ZNF804A) out of 10 genome-wide supported SZ-associated genes are part of an interacting network (including SMARCA2), 5 members of which encode transcription regulators. The expression of 3 (TCF4, SMARCA2 and CSF2RA) of the 10 genome-wide supported SZ-associated genes is modified when the REST/NRSF-SWI/SNF chromatin-remodeling complex is experimentally manipulated in mouse cell lines and in transgenic mouse models. The REST/NRSF-SWI/SNF deregulation also results in the differential expression of genes that are clustered in chromosomes suggesting the induction of genome-wide epigenetic changes. Finally, we found that SMARCA2 interactors and the genome-wide supported SZ-associated genes are considerably enriched in genes displaying positive selection in primates and in the human lineage which suggests the occurrence of novel protein interactions in primates. Altogether, these data identify the SWI/SNF chromatin-remodeling complex as a key component of the genetic architecture of SZ. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 8 | Schizophr Bull 2010 May 36: 443-7 |
| PMID | 20421335 |
| Title | TCF4, schizophrenia, and Pitt-Hopkins Syndrome. |
| Abstract | Genome-wide association studies allied with the identification of rare copy number variants have provided important insights into the genetic risk factors for schizophrenia. Recently, a meta-analysis of several genome-wide association studies found, in addition to several other markers, a single nucleotide polymorphism in intron 4 of the TCF4 gene that was associated with schizophrenia. TCF4 encodes a basic helix-loop-helix transcription factor that interacts with other transcription factors to activate or repress gene expression. TCF4 mutations also cause Pitt-Hopkins Syndrome, an autosomal-dominant neurodevelopmental disorder associated with severe mental retardation. Variants in the TCF4 gene may therefore be associated with a range of neuropsychiatric phenotypes, including schizophrenia. Recessive forms of Pitt-Hopkins syndrome are caused by mutations in NRXN1 and CNTNAP2. Interestingly, NRXN1 deletions have been reported in schizophrenia, whereas CNTNAP2 variants are associated with several neuropsychiatric phenotypes. These data suggest that TCF4, NRXN1, and CNTNAP2 may participate in a biological pathway that is altered in patients with schizophrenia and other neuropsychiatric disorders. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 9 | Biol. Psychiatry 2010 Jul 68: 33-40 |
| PMID | 20434134 |
| Title | Cognitive and sensorimotor gating impairments in transgenic mice overexpressing the schizophrenia susceptibility gene Tcf4 in the brain. |
| Abstract | The combined analysis of several large genome-wide association studies identified the basic helix-loop-helix (bHLH) transcription factor TCF4 as one of the most significant schizophrenia susceptibility genes. Its function in the adult brain, however, is not known. TCF4 belongs to the E-protein subfamily known to be involved in neurodevelopment. The messenger RNA expression of TCF4 is sustained in the adult mouse brain, suggesting a function in the adult nervous system. TCF4 null mutant mice die perinatally, and haploinsufficiency of TCF4 in humans causes severe mental retardation. To investigate the possible function of TCF4 in the adult central nervous system, we generated transgenic mice that moderately overexpress TCF4 postnatally in the brain to reduce the risk of developmental effects possibly interfering with adult brain functions. TCF4 transgenic mice were characterized with molecular, histological, and behavioral methods. TCF4 transgenic mice display profound deficits in contextual and cued fear conditioning and sensorimotor gating. Furthermore, we show that TCF4 interacts with the neurogenic bHLH factors NEUROD and NDRF in vivo. Molecular analyses revealed the dynamic circadian deregulation of neuronal bHLH factors in the adult hippocampus. We conclude that TCF4 likely acts in concert with other neuronal bHLH transcription factors contributing to higher-order cognitive processing. Moderate transcriptional deregulation of TCF4 in the brain interferes with cognitive functions and might alter circadian processes in mice. These observations provide insight for the first time into the physiological function of TCF4 in the adult brain and its possible contributions to neuropsychiatric disease conditions. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 10 | Hum. Mol. Genet. 2011 Jan 20: 387-91 |
| PMID | 21037240 |
| Title | Most genome-wide significant susceptibility loci for schizophrenia and bipolar disorder reported to date cross-traditional diagnostic boundaries. |
| Abstract | Recent findings from genetic epidemiology and from genome-wide association studies point strongly to a partial overlap in the genes that contribute susceptibility to schizophrenia and bipolar disorder (BD). Previous data have also directly implicated one of the best supported schizophrenia-associated loci, zinc finger binding protein 804A (ZNF804A), as showing trans-disorder effects, and the same is true for one of the best supported bipolar loci, calcium channel, voltage-dependent, L type, alpha 1C subunit (CACNA1C) which has also been associated with schizophrenia. We have undertaken a cross-phenotype study based upon the remaining variants that show genome-wide evidence for association in large schizophrenia and BD meta-analyses. These comprise in schizophrenia, SNPs in or in the vicinity of transcription factor 4 (TCF4), neurogranin (NRGN) and an extended region covering the MHC locus on chromosome 6. For BD, the strongly supported variants are in the vicinity of ankyrin 3, node of Ranvier (ANK3) and polybromo-1 (PBRM1). Using data sets entirely independent of their original discoveries, we observed strong evidence that the PBRM1 locus is also associated with schizophrenia (P = 0.00015) and nominally significant evidence (P < 0.05) that the NRGN and the extended MHC region are associated with BD. Moreover, considering this highly restricted set of loci as a group, the evidence for trans-disorder effects is compelling (P = 4.7 × 10(-5)). Including earlier reported data for trans-disorder effects for ZNF804A and CACNA1C, six out of eight of the most robustly associated loci for either disorder show trans-disorder effects. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 11 | Front Behav Neurosci 2011 -1 5: 85 |
| PMID | 22347851 |
| Title | Adenomatous polyposis coli heterozygous knockout mice display hypoactivity and age-dependent working memory deficits. |
| Abstract | A tumor suppressor gene, Adenomatous polyposis coli (Apc), is expressed in the nervous system from embryonic to adulthood stages, and transmits the Wnt signaling pathway in which schizophrenia susceptibility genes, including T-cell factor 4 (TCF4) and calcineurin (CN), are involved. However, the functions of Apc in the nervous system are largely unknown. In this study, as the first evaluation of Apc function in the nervous system, we have investigated the behavioral significance of the Apc gene, applying a battery of behavioral tests to Apc heterozygous knockout (Apc(+/-)) mice. Apc(+/-) mice showed no significant impairment in neurological reflexes or sensory and motor abilities. In various tests, including light/dark transition, open-field, social interaction, eight-arm radial maze, and fear conditioning tests, Apc(+/-) mice exhibited hypoactivity. In the eight-arm radial maze, Apc(+/-) mice 6-7 weeks of age displayed almost normal performance, whereas those 11-12 weeks of age showed a severe performance deficit in working memory, suggesting that Apc is involved in working memory performance in an age-dependent manner. The possibility that anemia, which Apc(+/-) mice develop by 17 weeks of age, impairs working memory performance, however, cannot be excluded. Our results suggest that Apc plays a role in the regulation of locomotor activity and presumably working memory performance. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 12 | Hum. Mol. Genet. 2011 Oct 20: 4076-81 |
| PMID | 21791550 |
| Title | Common variants at VRK2 and TCF4 conferring risk of schizophrenia. |
| Abstract | Common sequence variants have recently joined rare structural polymorphisms as genetic factors with strong evidence for association with schizophrenia. Here we extend our previous genome-wide association study and meta-analysis (totalling 7 946 cases and 19 036 controls) by examining an expanded set of variants using an enlarged follow-up sample (up to 10 260 cases and 23 500 controls). In addition to previously reported alleles in the major histocompatibility complex region, near neurogranin (NRGN) and in an intron of transcription factor 4 (TCF4), we find two novel variants showing genome-wide significant association: rs2312147[C], upstream of vaccinia-related kinase 2 (VRK2) [odds ratio (OR) = 1.09, P = 1.9 × 10(-9)] and rs4309482[A], between coiled-coiled domain containing 68 (CCDC68) and TCF4, about 400 kb from the previously described risk allele, but not accounted for by its association (OR = 1.09, P = 7.8 × 10(-9)). |
| SCZ Keywords | schizophrenia, schizophrenic |
| 13 | Neuropsychobiology 2011 -1 63: 131-6 |
| PMID | 21228604 |
| Title | Novel schizophrenia risk gene TCF4 influences verbal learning and memory functioning in schizophrenia patients. |
| Abstract | Recently, a role of the transcription factor 4 (TCF4) gene in schizophrenia has been reported in a large genome-wide association study. It has been hypothesized that TCF4 affects normal brain development and TCF4 has been related to different forms of neurodevelopmental disorders. schizophrenia patients exhibit strong impairments of verbal declarative memory (VDM) functions. Thus, we hypothesized that the disease-associated C allele of the rs9960767 polymorphism of the TCF4 gene led to impaired VDM functioning in schizophrenia patients. The TCF4 variant was genotyped in 401 schizophrenia patients. VDM functioning was measured using the Rey Auditory Verbal Learning Test (RAVLT). Carriers of the C allele were less impaired in recognition compared to those carrying the AA genotype (13.76 vs. 13.06; p = 0.049). Moreover, a trend toward higher scores in patients with the risk allele was found for delayed recall (10.24 vs. 9.41; p = 0.088). The TCF4 genotype did not influence intelligence or RAVLT immediate recall or total verbal learning. VDM function is influenced by the TCF4 gene in schizophrenia patients. However, the elevated risk for schizophrenia is not conferred by TCF4-mediated VDM impairment. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 14 | PLoS ONE 2011 -1 6: e22138 |
| PMID | 21789225 |
| Title | Functional diversity of human basic helix-loop-helix transcription factor TCF4 isoforms generated by alternative 5' exon usage and splicing. |
| Abstract | Transcription factor 4 (TCF4 alias ITF2, E2-2, ME2 or SEF2) is a ubiquitous class A basic helix-loop-helix protein that binds to E-box DNA sequences (CANNTG). While involved in the development and functioning of many different cell types, recent studies point to important roles for TCF4 in the nervous system. Specifically, human TCF4 gene is implicated in susceptibility to schizophrenia and TCF4 haploinsufficiency is the cause of the Pitt-Hopkins mental retardation syndrome. However, the structure, expression and coding potential of the human TCF4 gene have not been described in detail. In the present study we used human tissue samples to characterize human TCF4 gene structure and TCF4 expression at mRNA and protein level. We report that although widely expressed, human TCF4 mRNA expression is particularly high in the brain. We demonstrate that usage of numerous 5' exons of the human TCF4 gene potentially yields in TCF4 protein isoforms with 18 different N-termini. In addition, the diversity of isoforms is increased by alternative splicing of several internal exons. For functional characterization of TCF4 isoforms, we overexpressed individual isoforms in cultured human cells. Our analysis revealed that subcellular distribution of TCF4 isoforms is differentially regulated: Some isoforms contain a bipartite nuclear localization signal and are exclusively nuclear, whereas distribution of other isoforms relies on heterodimerization partners. Furthermore, the ability of different TCF4 isoforms to regulate E-box controlled reporter gene transcription is varied depending on whether one or both of the two TCF4 transcription activation domains are present in the protein. Both TCF4 activation domains are able to activate transcription independently, but act synergistically in combination. Altogether, in this study we have described the inter-tissue variability of TCF4 expression in human and provided evidence about the functional diversity of the alternative TCF4 protein isoforms. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 15 | J. Neurosci. 2011 May 31: 6684-91 |
| PMID | 21543597 |
| Title | The schizophrenia risk allele C of the TCF4 rs9960767 polymorphism disrupts sensorimotor gating in schizophrenia spectrum and healthy volunteers. |
| Abstract | In a large-scale meta-analysis, it has been recently shown that the transcription factor 4 (TCF4) gene is among the most prominent susceptibility genes for schizophrenia. Moreover, transgenic mice overexpressing TCF4 in the brain display a reduction of sensorimotor gating measured by prepulse inhibition (PPI) of the acoustic startle response (ASR). PPI is heritable and has been established as an important translational endophenotype of schizophrenia. We therefore investigated the impact of the schizophrenia susceptibility gene TCF4 (rs9960767) on sensorimotor gating of the ASR in healthy humans and in patients with a schizophrenia spectrum disorder. We assessed PPI, startle reactivity, and habituation of the ASR in two independent samples. The first sample consisted of 107 healthy volunteers from London, UK. The second sample was a schizophrenia spectrum group (n = 113) of 73 schizophrenia patients and 40 individuals at high risk for schizophrenia from Bonn, Germany (total sample n = 220). In both samples, PPI was strongly decreased in carriers of the schizophrenia risk allele C of the TCF4 gene (meta-analysis across both samples: p = 0.00002), whereas startle reactivity and habituation were unaffected by TCF4 genotype. Sensorimotor gating is modulated by TCF4 genotype, indicating an influential role of TCF4 gene variations in the development of early information-processing deficits in schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 16 | Eur Arch Psychiatry Clin Neurosci 2011 Nov 261 Suppl 2: S161-5 |
| PMID | 21932083 |
| Title | Impact of TCF4 on the genetics of schizophrenia. |
| Abstract | Mutations of the transcription factor 4 (TCF4) gene cause mental retardation with or without associated facial dysmorphisms and intermittent hyperventilation. Subsequently, a polymorphism of TCF4 was shown in a genome-wide association study to slightly increase the risk of schizophrenia. We have further analysed the impact of this TCF4 variant rs9960767 on early information processing and cognitive functions in schizophrenia patients. We have shown in a sample of 401 schizophrenia patients that TCF4 influences verbal memory in the Rey Auditory Verbal Learning Test. Contrary to expectations, carriers of the schizophrenia-associated allele showed better recognition, thus indicating that while TCF4 influences verbal memory, the TCF4-mediated schizophrenia risk is not determined by the influence of TCF4 on verbal memory. TCF4 does not impact on various other cognitive functions belonging to the domains of attention and executive functions. Moreover, in a pharmacogenetic approach, TCF4 does not modulate the improvement of positive or negative schizophrenia symptoms during treatment with antipsychotics. Finally, we have assessed a key electrophysiological endophenotype of schizophrenia, sensorimotor gating. As measured by prepulse inhibition, the schizophrenia risk allele C of TCF4 rs9960767 reduces sensorimotor gating. This indicates that TCF4 influences key mechanisms of information processing, which may contribute to the pathogenesis of schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 17 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2011 Dec 156B: 781-4 |
| PMID | 21812098 |
| Title | Association between TCF4 and schizophrenia does not exert its effect by common nonsynonymous variation or by influencing cis-acting regulation of mRNA expression in adult human brain. |
| Abstract | Large collaborative Genome-wide Association studies of schizophrenia have identified genes and genomic regions that are associated with the disorder at highly stringent levels of statistical significance. Among these, transcription factor 4 (TCF4) is one of the best supported although the associated SNP (rs9960767) is located within intron 3 and has no obvious function. Seeking the mechanism at TCF responsible for the association, we examined TCF4 for coding variants, and for cis regulated variation in TCF4 gene expression correlated with the associated SNP using an assay to detect differential allelic expression. Using data from the 1000 genomes project, we were unable to identify any nonsynonymous coding variants at the locus. Allele specific expression analysis using human post mortem brain samples revealed no evidence for cis-regulated mRNA expression related to genotype at the schizophrenia associated SNP. We conclude that association between schizophrenia and TCF4 is not mediated by a relatively common non-synonymous variant, or by a variant that alters mRNA expression as measured in adult human brain. It remains possible that the risk allele at this locus exerts effects on expression exclusively in a developmental context, in cell types or brain regions not adequately represented in our analysis, or through post-transcriptional effects, for example in the abundance of the protein or its sub-cellular distribution. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 18 | Mol. Psychiatry 2012 Sep 17: 887-905 |
| PMID | 22584867 |
| Title | Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction. |
| Abstract | We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 19 | Cell 2012 Apr 149: 525-37 |
| PMID | 22521361 |
| Title | Sequencing chromosomal abnormalities reveals neurodevelopmental loci that confer risk across diagnostic boundaries. |
| Abstract | Balanced chromosomal abnormalities (BCAs) represent a relatively untapped reservoir of single-gene disruptions in neurodevelopmental disorders (NDDs). We sequenced BCAs in patients with autism or related NDDs, revealing disruption of 33 loci in four general categories: (1) genes previously associated with abnormal neurodevelopment (e.g., AUTS2, FOXP1, and CDKL5), (2) single-gene contributors to microdeletion syndromes (MBD5, SATB2, EHMT1, and SNURF-SNRPN), (3) novel risk loci (e.g., CHD8, KIRREL3, and ZNF507), and (4) genes associated with later-onset psychiatric disorders (e.g., TCF4, ZNF804A, PDE10A, GRIN2B, and ANK3). We also discovered among neurodevelopmental cases a profoundly increased burden of copy-number variants from these 33 loci and a significant enrichment of polygenic risk alleles from genome-wide association studies of autism and schizophrenia. Our findings suggest a polygenic risk model of autism and reveal that some neurodevelopmental genes are sensitive to perturbation by multiple mutational mechanisms, leading to variable phenotypic outcomes that manifest at different life stages. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 20 | Schizophr. Res. 2012 Oct 141: 60-4 |
| PMID | 22883350 |
| Title | Experimental validation of candidate schizophrenia gene ZNF804A as target for hsa-miR-137. |
| Abstract | MicroRNAs (miRNAs) are small non-coding RNAs that mainly function as negative regulators of gene expression (Lai, 2002) and have been shown to be involved in schizophrenia etiology through genetic and expression studies (Burmistrova et al., 2007; Hansen et al., 2007a; Perkins et al., 2007; Beveridge et al., 2010; Kim et al., 2010). In a mega analysis of genome-wide association study (GWAS) of schizophrenia (SZ) and bipolar disorders (BP), a polymorphism (rs1625579) located in the primary transcript of a miRNA gene, hsa-miR-137, was reported to be strongly associated with SZ. Four SZ loci (CACNA1C, TCF4, CSMD1, C10orf26) achieving genome-wide significance in the same study were predicted and later experimentally validated (Kwon et al., 2011) as hsa-miR-137 targets. Here, using in silico, cellular and luciferase based approaches we also provide evidence that another well replicated candidate schizophrenia gene, ZNF804A, is also target for hsa-miR-137. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 21 | Biol. Psychiatry 2012 Oct 72: 620-8 |
| PMID | 22883433 |
| Title | Genome-wide association study implicates HLA-C*01:02 as a risk factor at the major histocompatibility complex locus in schizophrenia. |
| Abstract | We performed a genome-wide association study (GWAS) to identify common risk variants for schizophrenia. The discovery scan included 1606 patients and 1794 controls from Ireland, using 6,212,339 directly genotyped or imputed single nucleotide polymorphisms (SNPs). A subset of this sample (270 cases and 860 controls) was subsequently included in the Psychiatric GWAS Consortium-schizophrenia GWAS meta-analysis. One hundred eight SNPs were taken forward for replication in an independent sample of 13,195 cases and 31,021 control subjects. The most significant associations in discovery, corrected for genomic inflation, were (rs204999, p combined = 1.34 × 10(-9) and in combined samples (rs2523722 p combined = 2.88 × 10(-16)) mapped to the major histocompatibility complex (MHC) region. We imputed classical human leukocyte antigen (HLA) alleles at the locus; the most significant finding was with HLA-C*01:02. This association was distinct from the top SNP signal. The HLA alleles DRB1*03:01 and B*08:01 were protective, replicating a previous study. This study provides further support for involvement of MHC class I molecules in schizophrenia. We found evidence of association with previously reported risk alleles at the TCF4, VRK2, and ZNF804A loci. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 22 | Neurosci Biobehav Rev 2012 Jan 36: 556-71 |
| PMID | 21946175 |
| Title | Genome wide association studies (GWAS) and copy number variation (CNV) studies of the major psychoses: what have we learnt? |
| Abstract | schizophrenia (SZ) and bipolar disorder (BPD) have high heritabilities and are clinically and genetically complex. Genome wide association studies (GWAS) and studies of copy number variations (CNV) in SZ and BPD have allowed probing of their underlying genetic risks. In this systematic review, we assess extant genetic signals from published GWAS and CNV studies of SZ and BPD up till March 2011. Risk genes associated with SZ at genome wide significance level (p value<7.2 × 10(-8)) include zinc finger binding protein 804A (ZNF804A), major histocompatibility (MHC) region on chromosome 6, neurogranin (NRGN) and transcription factor 4 (TCF4). Risk genes associated with BPD include ankyrin 3, node of Ranvier (ANK3), calcium channel, voltage dependent, L type, alpha 1C subunit (CACNA1C), diacylglycerol kinase eta (DGKH), gene locus on chromosome 16p12, and polybromo-1 (PBRM1) and very recently neurocan gene (NCAN). Possible common genes underlying psychosis include ZNF804A, CACNA1C, NRGN and PBRM1. The CNV studies suggest that whilst CNVs are found in both SZ and BPD, the large deletions and duplications are more likely found in SZ rather than BPD. The validation of any genetic signal is likely confounded by genetic and phenotypic heterogeneities which are influenced by epistatic, epigenetic and gene-environment interactions. There is a pressing need to better integrate the multiple research platforms including systems biology computational models, genomics, cross disorder phenotyping studies, transcriptomics, proteomics, metabolomics, neuroimaging and clinical correlations in order to get us closer to a more enlightened understanding of the genetic and biological basis underlying these potentially crippling conditions. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 23 | Transl Psychiatry 2012 -1 2: e113 |
| PMID | 22832957 |
| Title | Association between SNPs and gene expression in multiple regions of the human brain. |
| Abstract | Identifying the genetic cis associations between DNA variants (single-nucleotide polymorphisms (SNPs)) and gene expression in brain tissue may be a promising approach to find functionally relevant pathways that contribute to the etiology of psychiatric disorders. In this study, we examined the association between genetic variations and gene expression in prefrontal cortex, hippocampus, temporal cortex, thalamus and cerebellum in subjects with psychiatric disorders and in normal controls. We identified cis associations between 648 transcripts and 6725 SNPs in the various brain regions. Several SNPs showed brain regional-specific associations. The expression level of only one gene, PDE4DIP, was associated with a SNP, rs12124527, in all the brain regions tested here. From our data, we generated a list of brain cis expression quantitative trait loci (eQTL) genes that we compared with a list of schizophrenia candidate genes downloaded from the schizophrenia Forum (SZgene) database (http://www.szgene.org/). Of the SZgene candidate genes, we found that the expression levels of four genes, HTR2A, PLXNA2, SRR and TCF4, were significantly associated with cis SNPs in at least one brain region tested. One gene, SRR, was also involved in a coexpression module that we found to be associated with disease status. In addition, a substantial number of cis eQTL genes were also involved in the module, suggesting eQTL analysis of brain tissue may identify more reliable susceptibility genes for schizophrenia than case-control genetic association analyses. In an attempt to facilitate the identification of genetic variations that may underlie the etiology of major psychiatric disorders, we have integrated the brain eQTL results into a public and online database, Stanley Neuropathology Consortium Integrative Database (SNCID; http://sncid.stanleyresearch.org). |
| SCZ Keywords | schizophrenia, schizophrenic |
| 24 | Transl Psychiatry 2012 -1 2: e112 |
| PMID | 22832956 |
| Title | TCF4 sequence variants and mRNA levels are associated with neurodevelopmental characteristics in psychotic disorders. |
| Abstract | TCF4 is involved in neurodevelopment, and intergenic and intronic variants in or close to the TCF4 gene have been associated with susceptibility to schizophrenia. However, the functional role of TCF4 at the level of gene expression and relationship to severity of core psychotic phenotypes are not known. TCF4 mRNA expression level in peripheral blood was determined in a large sample of patients with psychosis spectrum disorders (n = 596) and healthy controls (n = 385). The previously identified TCF4 risk variants (rs12966547 (G), rs9960767 (C), rs4309482 (A), rs2958182 (T) and rs17512836 (C)) were tested for association with characteristic psychosis phenotypes, including neurocognitive traits, psychotic symptoms and structural magnetic resonance imaging brain morphometric measures, using a linear regression model. Further, we explored the association of additional 59 single nucleotide polymorphisms (SNPs) covering the TCF4 gene to these phenotypes. The rs12966547 and rs4309482 risk variants were associated with poorer verbal fluency in the total sample. There were significant associations of other TCF4 SNPs with negative symptoms, verbal learning, executive functioning and age at onset in psychotic patients and brain abnormalities in total sample. The TCF4 mRNA expression level was significantly increased in psychosis patients compared with controls and positively correlated with positive- and negative-symptom levels. The increase in TCF4 mRNA expression level in psychosis patients and the association of TCF4 SNPs with core psychotic phenotypes across clinical, cognitive and brain morphological domains support that common TCF4 variants are involved in psychosis pathology, probably related to abnormal neurodevelopment. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 25 | Proc. Natl. Acad. Sci. U.S.A. 2012 Apr 109: 6271-6 |
| PMID | 22451930 |
| Title | Schizophrenia risk polymorphisms in the TCF4 gene interact with smoking in the modulation of auditory sensory gating. |
| Abstract | Several polymorphisms of the transcription factor 4 (TCF4) have been shown to increase the risk for schizophrenia, particularly TCF4 rs9960767. This polymorphism is associated with impaired sensorimotor gating measured by prepulse inhibition--an established endophenotype of schizophrenia. We therefore investigated whether TCF4 polymorphisms also affect another proposed endophenotype of schizophrenia, namely sensory gating assessed by P50 suppression of the auditory evoked potential. Although sensorimotor gating and sensory gating are not identical, recent data suggest that they share genetic fundamentals. In a multicenter study at six academic institutions throughout Germany, we applied an auditory P50 suppression paradigm to 1,821 subjects (1,023 never-smokers, 798 smokers) randomly selected from the general population. Samples were genotyped for 21 TCF4 polymorphisms. Given that smoking is highly prevalent in schizophrenia and affects sensory gating, we also assessed smoking behavior, cotinine plasma concentrations, exhaled carbon monoxide, and the Fagerström Test (FTND). P50 suppression was significantly decreased in carriers of schizophrenia risk alleles of the TCF4 polymorphisms rs9960767, rs10401120rs, rs17597926, and 17512836 (P < 0.0002-0.00005). These gene effects were modulated by smoking behavior as indicated by significant interactions of TCF4 genotype and smoking status; heavy smokers (FTND score ? 4) showed stronger gene effects on P50 suppression than light smokers and never-smokers. Our finding suggests that sensory gating is modulated by an interaction of TCF4 genotype with smoking, and both factors may play a role in early information processing deficits also in schizophrenia. Consequently, considering smoking behavior may facilitate the search for genetic risk factors for schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 26 | Mol. Psychiatry 2013 Jan 18: 11-2 |
| PMID | 22182936 |
| Title | Validation of schizophrenia-associated genes CSMD1, C10orf26, CACNA1C and TCF4 as miR-137 targets. |
| Abstract | -1 |
| SCZ Keywords | schizophrenia, schizophrenic |
| 27 | J Psychiatr Res 2013 Sep 47: 1215-21 |
| PMID | 23786914 |
| Title | Analysis of miR-137 expression and rs1625579 in dorsolateral prefrontal cortex. |
| Abstract | MicroRNAs (miRNAs) are small non-coding RNAs that act as potent regulators of gene expression. A recent GWAS reported the rs1625579 SNP, located downstream of miR-137, as the strongest new association with schizophrenia [Ripke S, Sanders AR, Kendler KS, Levinson DF, Sklar P, Holmans PA, et al. Genome-wide association study identifies five new schizophrenia loci. Nat Genet 2011;43:969-76.]. Prior to this GWAS finding, a schizophrenia imaging-genetic study found miR-137 target genes significantly enriched for association with activation in the dorsolateral prefrontal cortex (DLPFC) [Potkin SG, Macciardi F, Guffanti G, Fallon JH, Wang Q, Turner JA, et al. Identifying gene regulatory networks in schizophrenia. Neuroimage 2010;53:839-47.]. We investigated the expression levels of miR-137 and three candidate target genes (ZNF804A, CACNA1C, TCF4) in the DLPFC of postmortem brain tissue from 2 independent cohorts: (1) 26 subjects (10 control (CTR), 7 schizophrenia (SZ), 9 bipolar disorder (BD)) collected at the UCI brain bank; and (2) 99 subjects (33 CTR, 35 SZ, 31 BD) obtained from the Stanley Medical Research Institute (SMRI). MiR-137 expression in the DLPFC did not differ between diagnoses. We also explored the relationship between rs1625579 genotypes and miR-137 expression. Significantly lower miR-137 expression levels were observed in the homozygous TT subjects compared to TG and GG subjects in the control group (30% decrease, p-value = 0.03). Moreover, reduced miR-137 levels in TT subjects corresponded to increased levels of the miR-137 target gene TCF4. The miR-137 expression pattern in 9 brain regions was significant for regional effect (ANOVA p-value = 1.83E-12), with amygdala and hippocampus having the highest miR-137 expression level. In conclusion, decreased miR-137 expression is associated with the SZ risk allele of rs1625579, and potential regulation of TCF4, another SZ candidate gene. This study offers additional support for involvement of miR-137 and downstream targets as mechanisms of risk for psychiatric disorders. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 28 | PLoS ONE 2013 -1 8: e73169 |
| PMID | 24058414 |
| Title | Knockdown of human TCF4 affects multiple signaling pathways involved in cell survival, epithelial to mesenchymal transition and neuronal differentiation. |
| Abstract | Haploinsufficiency of TCF4 causes Pitt-Hopkins syndrome (PTHS): a severe form of mental retardation with phenotypic similarities to Angelman, Mowat-Wilson and Rett syndromes. Genome-wide association studies have also found that common variants in TCF4 are associated with an increased risk of schizophrenia. Although TCF4 is transcription factor, little is known about TCF4-regulated processes in the brain. In this study we used genome-wide expression profiling to determine the effects of acute TCF4 knockdown on gene expression in SH-SY5Y neuroblastoma cells. We identified 1204 gene expression changes (494 upregulated, 710 downregulated) in TCF4 knockdown cells. Pathway and enrichment analysis on the differentially expressed genes in TCF4-knockdown cells identified an over-representation of genes involved in TGF-? signaling, epithelial to mesenchymal transition (EMT) and apoptosis. Among the most significantly differentially expressed genes were the EMT regulators, SNAI2 and DEC1 and the proneural genes, NEUROG2 and ASCL1. Altered expression of several mental retardation genes such as UBE3A (Angelman Syndrome), ZEB2 (Mowat-Wilson Syndrome) and MEF2C was also found in TCF4-depleted cells. These data suggest that TCF4 regulates a number of convergent signaling pathways involved in cell differentiation and survival in addition to a subset of clinically important mental retardation genes. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 29 | Front Genet 2013 -1 4: 58 |
| PMID | 23637704 |
| Title | Potential Impact of miR-137 and Its Targets in Schizophrenia. |
| Abstract | The significant impact of microRNAs (miRNAs) on disease pathology is becoming increasingly evident. These small non-coding RNAs have the ability to post-transcriptionally silence the expression of thousands of genes. Therefore, dysregulation of even a single miRNA could confer a large polygenic effect. schizophrenia is a genetically complex illness thought to involve multiple genes each contributing a small risk. Large genome-wide association studies identified miR-137, a miRNA shown to be involved in neuronal maturation, as one of the top risk genes. To assess the potential mechanism of impact of miR-137 in this disorder and identify its targets, we used a combination of literature searches, ingenuity pathway analysis (IPA), and freely accessible bioinformatics resources. Using TargetScan and the schizophrenia gene resource (SZGR) database, we found that in addition to CSMD1, C10orf26, CACNA1C, TCF4, and ZNF804A, five schizophrenia risk genes whose transcripts are also validated miR-137 targets, there are other schizophrenia-associated genes that may be targets of miR-137, including ERBB4, GABRA1, GRIN2A, GRM5, GSK3B, NRG2, and HTR2C. IPA analyses of all the potential targets identified several nervous system (NS) functions as the top canonical pathways including synaptic long-term potentiation, a process implicated in learning and memory mechanisms and recently shown to be altered in patients with schizophrenia. Among the subset of targets involved in NS development and function, the top scoring pathways were ephrin receptor signaling and axonal guidance, processes that are critical for proper circuitry formation and were shown to be disrupted in schizophrenia. These results suggest that miR-137 may indeed play a substantial role in the genetic etiology of schizophrenia by regulating networks involved in neural development and brain function. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 30 | Schizophr Bull 2013 May 39: 518-26 |
| PMID | 22499782 |
| Title | Brain vs behavior: an effect size comparison of neuroimaging and cognitive studies of genetic risk for schizophrenia. |
| Abstract | Genetic variants associated with increased risk for schizophrenia (SZ) are hypothesized to be more penetrant at the level of brain structure and function than at the level of behavior. However, to date the relative sensitivity of imaging vs cognitive measures of these variants has not been quantified. We considered effect sizes associated with cognitive and imaging studies of 9 robust SZ risk genes (DAOA, DISC1, DTNBP1, NRG1, RGS4, NRGN, CACNA1C, TCF4, and ZNF804A) published between January 2005-November 2011. Summary data was used to calculate estimates of effect size for each significant finding. The mean effect size for each study was categorized as small, medium, or large and the relative frequency of each category was compared between modalities and across genes. Random effects meta-analysis was used to consider the impact of experimental methodology on effect size. Imaging studies reported mostly medium or large effects, whereas cognitive investigations commonly reported small effects. Meta-analysis confirmed that imaging studies were associated with larger effects. Effect size estimates were negatively correlated with sample size but did not differ as a function of gene nor imaging modality. These observations support the notion that SZ risk variants show larger effects, and hence greater penetrance, when characterized using indices of brain structure and function than when indexed by cognitive measures. However, it remains to be established whether this holds true for individual risk variants, imaging modalities, or cognitive functions, and how such effects may be mediated by a relationship with sample size and other aspects of experimental variability. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 31 | In Silico Pharmacol 2013 -1 1: 15 |
| PMID | 25505659 |
| Title | Comparison of gene expression profiles in the blood, hippocampus and prefrontal cortex of rats. |
| Abstract | The comparability of gene expression between blood and brain tissues is a central issue in neuropsychiatric research where the analysis of molecular mechanisms in the brain is of high importance for the understanding of the diseases and the discovery of biomarkers. However, the accessibility of brain tissue is limited. Therefore, knowledge about how easily accessible peripheral tissue, e. g. blood, is comparable to and reflects gene expression of brain regions will help to advance neuropsychiatric research. Gene expression in the blood, hippocampus (HC) and prefrontal cortex (PFC) of genetically identical rats was compared using a genome-wide Affymetrix gene expression microarray covering 29,215 expressed genes. A total of 56.8% of 15,717 expressed genes were co-expressed in blood and at least one brain tissue, while 55.3% of all genes were co-expressed in all three tissues simultaneously. The overlapping genes included a set of genes of relevance to neuropsychiatric diseases, in particular bipolar disorder, schizophrenia and alcohol addiction. These genes included CLOCK, COMT, FAAH, NPY, NR3C1, NRGN, PBRM1, TCF4, and SYNE. This study provides baseline data on absolute gene expression and differences between gene expression in the blood, HC and PFC brain tissue of genetically identical rats. The present data represents a valuable resource for future studies as it might be used for first information on gene expression levels of genes of interest in blood and brain under baseline conditions. Limitations of our study comprise possible contamination of brain tissue with blood and the non-detection of genes with very low expression levels. Genes that are more highly expressed in the brain than in the blood are of particular interest since changes in their expression, e.g. due to disease status, or treatment, are likely to be detected in an experiment. In contrast, genes with higher expression in the blood than in the brain are less informative since their higher baseline levels could superimpose variation in brain. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 32 | Behav. Brain Res. 2013 Jan 237: 348-56 |
| PMID | 23069005 |
| Title | Deficits in trace fear memory in a mouse model of the schizophrenia risk gene TCF4. |
| Abstract | The basic helix-loop-helix (bHLH) transcription factor TCF4 was confirmed in the combined analysis of several large genome-wide association studies (GWAS) as one of the rare highly replicated significant schizophrenia (SZ) susceptibility genes in large case-control cohorts. Focused genetic association studies showed that TCF4 influences verbal learning and memory, and modulates sensorimotor gating. Mice overexpressing TCF4 in the forebrain (TCF4tg) display cognitive deficits in hippocampus-dependent learning tasks and impairment of prepulse inhibition, a well-established endophenotype of SZ. The spectrum of cognitive deficits in SZ subjects, however, is broad and covers attention, working memory, and anticipation. Collectively, these higher order cognitive processes and the recall of remote memories are thought to depend mainly on prefrontal cortical networks. To further investigate cognitive disturbances in TCF4tg mice, we employed the trace fear conditioning paradigm that requires attention and critically depends on the anterior cingulate cortex (ACC). We show that TCF4tg mice display deficits in recent and remote trace fear memory and are impaired at anticipating aversive stimuli. We also assessed mRNA expression of the neuronal activity-regulated gene Fos in the ACC and hippocampus. Upon trace conditioning, Fos expression is reduced in TCF4tg mice as compared to controls, which parallels cognitive impairments in this learning paradigm. Collectively, these data indicate that the reduced cognitive performance in TCF4tg mice includes deficits at the level of attention and behavioral anticipation. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 33 | Exp. Mol. Med. 2013 -1 45: e21 |
| PMID | 23640545 |
| Title | Pitt-Hopkins Syndrome: intellectual disability due to loss of TCF4-regulated gene transcription. |
| Abstract | TCF4 (transcription factor 4; E2-2, ITF2) is a transcription factor that when haplo-insufficient causes Pitt-Hopkins Syndrome (PTHS), an autism-spectrum disorder that is associated with pervasive developmental delay and severe intellectual disability. The TCF4 gene is also a risk factor with highly significant linkage to schizophrenia, presumably via overexpression of the TCF4 gene product in the central nervous system. This review will present an overview of the clinical manifestations of PTHS and relate those clinical attributes to the underlying molecular genetics of TCF4. In order to provide a molecular biological context for the loss of function of TCF4 in PTHS, the review will also present a brief overview of the basic biochemistry of TCF4-mediated regulation of cellular and neuronal gene expression. In the final section of this review, I will discuss and speculate upon possible roles for the TCF4 transcription factor in neuronal function and comment upon how understanding these roles may give new insights into the molecular neurobiology of human cognition. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 34 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2013 Jan 162B: 1-16 |
| PMID | 23129290 |
| Title | TCF4 (e2-2; ITF2): a schizophrenia-associated gene with pleiotropic effects on human disease. |
| Abstract | Common SNPs in the transcription factor 4 (TCF4; ITF2, E2-2, SEF-2) gene, which encodes a basic Helix-Loop-Helix (bHLH) transcription factor, are associated with schizophrenia, conferring a small increase in risk. Other common SNPs in the gene are associated with the common eye disorder Fuch's corneal dystrophy, while rare, mostly de novo inactivating mutations cause Pitt-Hopkins syndrome. In this review, we present a systematic bioinformatics and literature review of the genomics, biological function and interactome of TCF4 in the context of schizophrenia. The TCF4 gene is present in all vertebrates, and although protein length varies, there is high conservation of primary sequence, including the DNA binding domain. Humans have a unique leucine-rich nuclear export signal. There are two main isoforms (A and B), as well as complex splicing generating many possible N-terminal amino acid sequences. TCF4 is highly expressed in the brain, where plays a role in neurodevelopment, interacting with class II bHLH transcription factors Math1, HASH1, and neuroD2. The Ca(2+) sensor protein calmodulin interacts with the DNA binding domain of TCF4, inhibiting transcriptional activation. It is also the target of microRNAs, including mir137, which is implicated in schizophrenia. The schizophrenia-associated SNPs are in linkage disequilibrium with common variants within putative DNA regulatory elements, suggesting that regulation of expression may underlie association with schizophrenia. Combined gene co-expression analyses and curated protein-protein interaction data provide a network involving TCF4 and other putative schizophrenia susceptibility genes. These findings suggest new opportunities for understanding the molecular basis of schizophrenia and other mental disorders. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 35 | JAMA Psychiatry 2013 Jun 70: 573-81 |
| PMID | 23894747 |
| Title | A comprehensive family-based replication study of schizophrenia genes. |
| Abstract | schizophrenia (SCZ) is a devastating psychiatric condition. Identifying the specific genetic variants and pathways that increase susceptibility to SCZ is critical to improve disease understanding and address the urgent need for new drug targets. To identify SCZ susceptibility genes. We integrated results from a meta-analysis of 18 genome-wide association studies (GWAS) involving 1,085,772 single-nucleotide polymorphisms (SNPs) and 6 databases that showed significant informativeness for SCZ. The 9380 most promising SNPs were then specifically genotyped in an independent family-based replication study that, after quality control, consisted of 8107 SNPs. Linkage meta-analysis, brain transcriptome meta-analysis, candidate gene database, OMIM, relevant mouse studies, and expression quantitative trait locus databases. We included 11,185 cases and 10,768 control subjects from 6 databases and, after quality control 6298 individuals (including 3286 cases) from 1811 nuclear families. Case-control status for SCZ. Replication results showed a highly significant enrichment of SNPs with small P values. Of the SNPs with replication values of P.01, the proportion of SNPs that had the same direction of effects as in the GWAS meta-analysis was 89% in the combined ancestry group (sign test, P < 2.20 x 10(-16) and 93% in subjects of European ancestry only (P < 2.20 < 10(-16)). Our results supported the major histocompatibility complex region showing a3.7-fold overall enrichment of replication values of P < .01 in subjects from European ancestry. We replicated SNPs in TCF4 (P = 2.53 x 10(-10)) and NOTCH4 (P = 3.16 x 10(-7)) that are among the most robust SCZ findings. More novel findings included POM121L2 (P = 3.51 x 10(-7)), AS3MT (P = 9.01 x 10(-7)), CNNM2 (P = 6.07 = 10(-7)), and NT5C2(P = 4.09 x 10(-7)). To explore the many small effects, we performed pathway analyses. The most significant pathways involved neuronal function (axonal guidance, neuronal systems, and L1 cell adhesion molecule interaction)and the immune system (antigen processing, cell adhesion molecules relevant to T cells, and translocation to immunological synapse). We replicated novel SCZ disease genes and pathogenic pathways. Better understanding the molecular and biological mechanisms involved with schizophrenia may improve disease management and may identify new drug targets. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 36 | Neuropsychopharmacology 2013 Mar 38: 683-9 |
| PMID | 23249814 |
| Title | Associations between TCF4 gene polymorphism and cognitive functions in schizophrenia patients and healthy controls. |
| Abstract | The SNP rs2958182 was reported to be significantly associated with schizophrenia (SCZ) in Han Chinese. This study examined this SNP's associations with cognitive functions in 580 SCZ patients and 498 controls. Cognitive functions were assessed using the Wechsler Adult Intelligence Scale-Revised (WAIS-RC), the Attention Network Task (ANT), the Stroop task, the dot pattern expectancy (DPX), task and the N-back working memory task. Results showed significant or marginally significant interaction effects between genotype and diagnosis status on IQ (P=0.011) and attention-related tasks (ie, the forward digit span of WAIS-RC, P=0.005; the ANT conflict effect; P=0.020, and its ratios over mean reaction time (RT), P=0.036; the Stroop conflict effect, P=0.032, and its ratios over mean RT, P=0.062; and the DPX task's error rate under the BX condition, P<0.001, and the error rate of BX minus the error rate of AY (BX-AY), P=0.002). There were no such interaction effects on the measures of working memory (all P-values >0.05). Further analysis of the significant genotype-by-diagnosis interactions showed that the risk (T) allele was associated with better performance on cognitive tasks in patients but with worse performance in controls. These results seem to indicate that the association between this SNP and selected cognitive functions may be of an inverted U-shaped pattern. Future research is needed to replicate these results and to explore the biochemical mechanisms behind this association. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 37 | Psychiatry Res 2014 Jan 215: 255-7 |
| PMID | 24210665 |
| Title | Absence of low frequency variants associated with schizophrenia at the ultraconserved non-coding region of TCF4. |
| Abstract | -1 |
| SCZ Keywords | schizophrenia, schizophrenic |
| 38 | Front Neurosci 2014 -1 8: 331 |
| PMID | 25414627 |
| Title | Neuroinformatic analyses of common and distinct genetic components associated with major neuropsychiatric disorders. |
| Abstract | Major neuropsychiatric disorders are highly heritable, with mounting evidence suggesting that these disorders share overlapping sets of molecular and cellular underpinnings. In the current article we systematically test the degree of genetic commonality across six major neuropsychiatric disorders-attention deficit hyperactivity disorder (ADHD), anxiety disorders (Anx), autistic spectrum disorders (ASD), bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia (SCZ). We curated a well-vetted list of genes based on large-scale human genetic studies based on the NHGRI catalog of published genome-wide association studies (GWAS). A total of 180 genes were accepted into the analysis on the basis of low but liberal GWAS p-values (<10(-5)). 22% of genes overlapped two or more disorders. The most widely shared subset of genes-common to five of six disorders-included ANK3, AS3MT, CACNA1C, CACNB2, CNNM2, CSMD1, DPCR1, ITIH3, NT5C2, PPP1R11, SYNE1, TCF4, TENM4, TRIM26, and ZNRD1. Using a suite of neuroinformatic resources, we showed that many of the shared genes are implicated in the postsynaptic density (PSD), expressed in immune tissues and co-expressed in developing human brain. Using a translational cross-species approach, we detected two distinct genetic components that were both shared by each of the six disorders; the 1st component is involved in CNS development, neural projections and synaptic transmission, while the 2nd is implicated in various cytoplasmic organelles and cellular processes. Combined, these genetic components account for 20-30% of the genetic load. The remaining risk is conferred by distinct, disorder-specific variants. Our systematic comparative analysis of shared and unique genetic factors highlights key gene sets and molecular processes that may ultimately translate into improved diagnosis and treatment of these debilitating disorders. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 39 | Schizophr. Res. 2014 Nov 159: 329-32 |
| PMID | 25217366 |
| Title | No effect of schizophrenia risk genes MIR137, TCF4, and ZNF804A on macroscopic brain structure. |
| Abstract | Single nucleotide polymorphisms (SNPs) within the MIR137, TCF4, and ZNF804A genes show genome-wide association to schizophrenia. However, the biological basis for the associations is unknown. Here, we tested the effects of these genes on brain structure in 1300 healthy adults. Using volumetry and voxel-based morphometry, neither gene-wide effects--including the combined effect of the genes--nor single SNP effects--including specific psychosis risk SNPs--were found on total brain volume, grey matter, white matter, or hippocampal volume. These results suggest that the associations between these risk genes and schizophrenia are unlikely to be mediated via effects on macroscopic brain structure. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 40 | Trends Mol Med 2014 Jun 20: 322-31 |
| PMID | 24594265 |
| Title | The emerging roles of TCF4 in disease and development. |
| Abstract | Genome-wide association studies have identified common variants in transcription factor 4 (TCF4) as susceptibility loci for schizophrenia, Fuchs' endothelial corneal dystrophy, and primary sclerosing cholangitis. By contrast, rare TCF4 mutations cause Pitt-Hopkins syndrome, a disorder characterized by intellectual disability and developmental delay, and have also been described in patients with other neurodevelopmental disorders. TCF4 therefore sits at the nexus between common and rare disorders. TCF4 interacts with other basic helix-loop-helix proteins, forming transcriptional networks that regulate the differentiation of several distinct cell types. Here, we review the role of TCF4 in these seemingly diverse disorders and discuss recent data implicating TCF4 as an important regulator of neurodevelopment and epithelial-mesenchymal transition. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 41 | Cell. Mol. Life Sci. 2014 Aug 71: 2815-35 |
| PMID | 24413739 |
| Title | Transcription factor 4 (TCF4) and schizophrenia: integrating the animal and the human perspective. |
| Abstract | schizophrenia is a genetically complex disease considered to have a neurodevelopmental pathogenesis and defined by a broad spectrum of positive and negative symptoms as well as cognitive deficits. Recently, large genome-wide association studies have identified common alleles slightly increasing the risk for schizophrenia. Among the few schizophrenia-risk genes that have been consistently replicated is the basic Helix-Loop-Helix (bHLH) transcription factor 4 (TCF4). Haploinsufficiency of the TCF4 (formatting follows IUPAC nomenclature: TCF4 protein/protein function, TCF4 rodent gene cDNA mRNA, TCF4 human gene cDNA mRNA) gene causes the Pitt-Hopkins syndrome-a neurodevelopmental disease characterized by severe mental retardation. Accordingly, TCF4 null-mutant mice display developmental brain defects. TCF4-associated risk alleles are located in putative coding and non-coding regions of the gene. Hence, subtle changes at the level of gene expression might be relevant for the etiopathology of schizophrenia. Behavioural phenotypes obtained with a mouse model of slightly increased gene dosage and electrophysiological investigations with human risk-allele carriers revealed an overlapping spectrum of schizophrenia-relevant endophenotypes. Most prominently, early information processing and higher cognitive functions appear to be associated with TCF4 risk genotypes. Moreover, a recent human study unravelled gene × environment interactions between TCF4 risk alleles and smoking behaviour that were specifically associated with disrupted early information processing. Taken together, TCF4 is considered as an integrator ('hub') of several bHLH networks controlling critical steps of various developmental, and, possibly, plasticity-related transcriptional programs in the CNS and changes of TCF4 expression also appear to affect brain networks important for information processing. Consequently, these findings support the neurodevelopmental hypothesis of schizophrenia and provide a basis for identifying the underlying molecular mechanisms. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 42 | Neurosci. Lett. 2014 May 568: 12-6 |
| PMID | 24686180 |
| Title | Expression analysis of the genes identified in GWAS of the postmortem brain tissues from patients with schizophrenia. |
| Abstract | Many gene expression studies have examined postmortem brain tissues of patients with schizophrenia. However, only a few expression studies of the genes identified in genome-wide association study (GWAS) have been published to date. We measured the expression levels of the genes identified in GWAS (ZNF804A, OPCML, RPGRIP1L, NRGN, and TCF4) of the postmortem brain tissues of patients with schizophrenia and controls from two separate sample sets (i.e., the Australian Tissue Resource Center and Stanley Medical Research Institute). We also determined whether the single-nucleotide polymorphisms (SNPs) identified in the GWAS were related to the gene expression changes in the prefrontal cortex. No difference was observed between the patients with schizophrenia and controls from the Australian Tissue Resource Center samples in the mRNA levels of ZNF804A, OPCML, RPGRIP1L, NRGN, or TCF4. The lack of mRNA change for these five transcripts was also found in the brain samples from the Stanley Medical Research Institute. In addition, no relationship between the schizophrenia-associated SNPs identified in the GWAS and the corresponding gene expression was observed in either sample set. Our results suggest that major changes in the transcript levels of the five candidate genes identified in the GWAS may not occur in adult patients with schizophrenia. The lack of linkage between the risk gene polymorphisms and the expression levels of their major transcripts suggests that the control of pan mRNA levels may not be a prominent mechanism by which the genes identified in the GWAS contribute to the pathophysiology of schizophrenia. Further studies are needed to examine how the genes identified in the GWAS contribute to the pathophysiology of schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 43 | PLoS ONE 2014 -1 9: e94398 |
| PMID | 24718684 |
| Title | Are genetic risk factors for psychosis also associated with dimension-specific psychotic experiences in adolescence? |
| Abstract | Psychosis has been hypothesised to be a continuously distributed quantitative phenotype and disorders such as schizophrenia and bipolar disorder represent its extreme manifestations. Evidence suggests that common genetic variants play an important role in liability to both schizophrenia and bipolar disorder. Here we tested the hypothesis that these common variants would also influence psychotic experiences measured dimensionally in adolescents in the general population. Our aim was to test whether schizophrenia and bipolar disorder polygenic risk scores (PRS), as well as specific single nucleotide polymorphisms (SNPs) previously identified as risk variants for schizophrenia, were associated with adolescent dimension-specific psychotic experiences. Self-reported Paranoia, Hallucinations, Cognitive Disorganisation, Grandiosity, Anhedonia, and Parent-rated Negative Symptoms, as measured by the Specific Psychotic Experiences Questionnaire (SPEQ), were assessed in a community sample of 2,152 16-year-olds. Polygenic risk scores were calculated using estimates of the log of odds ratios from the Psychiatric Genomics Consortium GWAS stage-1 mega-analysis of schizophrenia and bipolar disorder. The polygenic risk analyses yielded no significant associations between schizophrenia and bipolar disorder PRS and the SPEQ measures. The analyses on the 28 individual SNPs previously associated with schizophrenia found that two SNPs in TCF4 returned a significant association with the SPEQ Paranoia dimension, rs17512836 (p-value?=?2.57×10??) and rs9960767 (p-value?=?6.23×10??). Replication in an independent sample of 16-year-olds (N?=?3,427) assessed using the Psychotic-Like Symptoms Questionnaire (PLIKS-Q), a composite measure of multiple positive psychotic experiences, failed to yield significant results. Future research with PRS derived from larger samples, as well as larger adolescent validation samples, would improve the predictive power to test these hypotheses further. The challenges of relating adult clinical diagnostic constructs such as schizophrenia to adolescent psychotic experiences at a genetic level are discussed. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 44 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2014 Jan 165B: 9-18 |
| PMID | 24339136 |
| Title | Neurophysiologic effect of GWAS derived schizophrenia and bipolar risk variants. |
| Abstract | Genome-wide association studies (GWAS) have identified multiple single nucleotide polymorphisms (SNPs) as disease associated variants for schizophrenia (SCZ), bipolar disorder (BPD), or both. Although these results are statistically robust, the functional effects of these variants and their role in the pathophysiology of SCZ or BPD remain unclear. Dissecting the effects of risk genes on distinct domains of brain function can provide important biological insights into the mechanisms by which these genes may confer illness risk. This study used quantitative event related potentials to characterize the neurophysiological effects of well-documented GWAS-derived SCZ/BPD susceptibility variants in order to map gene effects onto important domains of brain function. We genotyped 199 patients with DSM-IV diagnoses of SCZ or BPD and 74 healthy control subjects for 19 risk SNPs derived from previous GWAS findings and tested their association with five neurophysiologic traits (P3 amplitude, P3 latency, N1 amplitude, P2 amplitude, and P50 sensory gating responses) known to be abnormal in psychosis. The TCF4 SNP rs17512836 risk allele showed a significant association with reduced auditory P3 amplitude (P?=?0.00016) after correction for multiple testing. The same allele was also associated with delayed P3 latency (P?=?0.005). Our results suggest that a SCZ risk variant in TCF4 is associated with neurophysiologic traits thought to index attention and working memory abnormalities in psychotic disorders. These findings suggest a mechanism by which TCF4 may contribute to the neurobiological basis of psychotic illness. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 45 | Schizophr. Res. 2014 Jan 152: 124-9 |
| PMID | 24275585 |
| Title | TCF4 gene polymorphism and cognitive performance in patients with first episode psychosis. |
| Abstract | Single nucleotide polymorphisms in TCF4 gene have been consistently associated with schizophrenia in genome wide association studies, including the C allele of rs9960767. However, its exact role in modulating the schizophrenia phenotype is not known. To comprehensively investigate the relationship between rs9960767 risk allele (C) of TCF4 and cognitive performance in patients with first episode psychosis (FEP). 173 patients with FEP received a comprehensive neurocognitive evaluation and were genotyped for rs9960767. Carriers of the risk allele (CA/CC) were compared to non-carriers (AA) using Multivariate Analysis of Covariance MANCOVA. Ethnicity, negative symptoms and substance abuse were included as covariates. Carriers of the risk allele had a statistically significant lower performance in the cognitive domain of Reasoning/Problem-Solving compared to non-carriers (F1,172=4.4, p=.038). There were no significant genotype effects on the other cognitive domains or general cognition. This effect on the Reasoning/Problem-Solving domain remained significant even when controlling for IQ (F1,172=4.3, p=.039). rs9960767 (C) of TCF4 appears to be associated with neurocognitive deficits in the Reasoning/Problem-Solving cognitive domain, in patients with FEP. A confirmation of this finding in a larger sample and including other TCF4 polymorphisms will be needed to gain further validity of this result. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 46 | Psychol Med 2015 -1 45: 2461-80 |
| PMID | 25858580 |
| Title | What is the impact of genome-wide supported risk variants for schizophrenia and bipolar disorder on brain structure and function? A systematic review. |
| Abstract | The powerful genome-wide association studies (GWAS) revealed common mutations that increase susceptibility for schizophrenia (SZ) and bipolar disorder (BD), but the vast majority were not known to be functional or associated with these illnesses. To help fill this gap, their impact on human brain structure and function has been examined. We systematically discuss this output to facilitate its timely integration in the psychosis research field; and encourage reflection for future research. Irrespective of imaging modality, studies addressing the effect of SZ/BD GWAS risk genes (ANK3, CACNA1C, MHC, TCF4, NRGN, DGKH, PBRM1, NCAN and ZNF804A) were included. Most GWAS risk variations were reported to affect neuroimaging phenotypes implicated in SZ/BD: white-matter integrity (ANK3 and ZNF804A), volume (CACNA1C and ZNF804A) and density (ZNF804A); grey-matter (CACNA1C, NRGN, TCF4 and ZNF804A) and ventricular (TCF4) volume; cortical folding (NCAN) and thickness (ZNF804A); regional activation during executive tasks (ANK3, CACNA1C, DGKH, NRGN and ZNF804A) and functional connectivity during executive tasks (CACNA1C and ZNF804A), facial affect recognition (CACNA1C and ZNF804A) and theory-of-mind (ZNF804A); but inconsistencies and non-replications also exist. Further efforts such as standardizing reporting and exploring complementary designs, are warranted to test the reproducibility of these early findings. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 47 | PLoS ONE 2015 -1 10: e0116686 |
| PMID | 25658856 |
| Title | Altered gene expression in schizophrenia: findings from transcriptional signatures in fibroblasts and blood. |
| Abstract | Whole-genome expression studies in the peripheral tissues of patients affected by schizophrenia (SCZ) can provide new insight into the molecular basis of the disorder and innovative biomarkers that may be of great utility in clinical practice. Recent evidence suggests that skin fibroblasts could represent a non-neural peripheral model useful for investigating molecular alterations in psychiatric disorders. A microarray expression study was conducted comparing skin fibroblast transcriptomic profiles from 20 SCZ patients and 20 controls. All genes strongly differentially expressed were validated by real-time quantitative PCR (RT-qPCR) in fibroblasts and analyzed in a sample of peripheral blood cell (PBC) RNA from patients (n = 25) and controls (n = 22). To evaluate the specificity for SCZ, alterations in gene expression were tested in additional samples of fibroblasts and PBCs RNA from Major Depressive Disorder (MDD) (n = 16; n = 21, respectively) and Bipolar Disorder (BD) patients (n = 15; n = 20, respectively). Six genes (JUN, HIST2H2BE, FOSB, FOS, EGR1, TCF4) were significantly upregulated in SCZ compared to control fibroblasts. In blood, an increase in expression levels was confirmed only for EGR1, whereas JUN was downregulated; no significant differences were observed for the other genes. EGR1 upregulation was specific for SCZ compared to MDD and BD. Our study reports the upregulation of JUN, HIST2H2BE, FOSB, FOS, EGR1 and TCF4 in the fibroblasts of SCZ patients. A significant alteration in EGR1 expression is also present in SCZ PBCs compared to controls and to MDD and BD patients, suggesting that this gene could be a specific biomarker helpful in the differential diagnosis of major psychoses. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 48 | Eur Arch Psychiatry Clin Neurosci 2015 Sep -1: -1 |
| PMID | 26404636 |
| Title | Tcf4 transgenic female mice display delayed adaptation in an auditory latent inhibition paradigm. |
| Abstract | schizophrenia (SZ) is a severe mental disorder affecting about 1 % of the human population. Patients show severe deficits in cognitive processing often characterized by an improper filtering of environmental stimuli. Independent genome-wide association studies confirmed a number of risk variants for SZ including several associated with the gene encoding the transcription factor 4 (TCF4). TCF4 is widely expressed in the central nervous system of mice and humans and seems to be important for brain development. Transgenic mice overexpressing murine TCF4 (TCF4tg) in the adult brain display cognitive impairments and sensorimotor gating disturbances. To address the question of whether increased TCF4 gene dosage may affect cognitive flexibility in an auditory associative task, we tested latent inhibition (LI) in female TCF4tg mice. LI is a widely accepted translational endophenotype of SZ and results from a maladaptive delay in switching a response to a previously unconditioned stimulus when this becomes conditioned. Using an Audiobox, we pre-exposed TCF4tg mice and their wild-type littermates to either a 3- or a 12-kHz tone before conditioning them to a 12-kHz tone. TCF4tg animals pre-exposed to a 12-kHz tone showed significantly delayed conditioning when the previously unconditioned tone became associated with an air puff. These results support findings that associate TCF4 dysfunction with cognitive inflexibility and improper filtering of sensory stimuli observed in SZ patients. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 49 | J Psychiatr Res 2015 Oct 69: 95-101 |
| PMID | 26343600 |
| Title | TCF4 gene polymorphism is associated with cognition in patients with schizophrenia and healthy controls. |
| Abstract | Cognitive deficits have been identified as an important core feature of schizophrenia. Single nucleotide polymorphisms in the transcription factor 4 (TCF4) gene have been reported to be involved in the susceptibility to schizophrenia and be significantly related to cognitive deficits of schizophrenia and controls. This study examines whether the TCF4 rs2958182 polymorphism influences cognitive functions in chronic schizophrenia and controls. The presence of the TCF4 rs2958182 was determined in 976 patients and 420 controls using a case-control design. We assessed all the patients' psychopathology using the Positive and Negative Syndrome Scale (PANSS). Cognition was assessed in 777 patients and 399 controls by using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). There were marginally significant differences in the TCF4 rs2958182 allelic and genotypic distributions between patients and controls (?2 = 3.48, p = 0.062 and ?2 = 0.036, p = 0.036, respectively). Cognitive test scores were significantly lower in patients than in controls on all scales (all p < 0.001) except for the visuospatial/constructional index (p > 0.05). There were significant genotype effects on delayed memory score (p = 0.013), the RBANS total score (p = 0.028) and language score (p = 0.034). Further analysis showed that the language score significantly differed according to the genotypic groups (A/A+T/A group versus T/T group) (p = 0.007) in patients but not in controls (p > 0.05), and the delayed memory score also significantly differed according to the genotypic groups (A/A+T/A group versus T/T group) (p = 0.021) in controls but not in patients (p > 0.05). This study found that the A allele of the TCF4 rs2958182 polymorphism was the risk allele of schizophrenia, and was associated with lower cognitive performance in language in schizophrenia and delayed memory in controls. In contrast, the T allele of this polymorphism was found to be the schizophrenia risk allele in another study in Han Chinese people. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 50 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2015 Jul 168B: 354-62 |
| PMID | 26010163 |
| Title | Investigation of the role of TCF4 rare sequence variants in schizophrenia. |
| Abstract | Transcription factor 4 (TCF4) is one of the most robust of all reported schizophrenia risk loci and is supported by several genetic and functional lines of evidence. While numerous studies have implicated common genetic variation at TCF4 in schizophrenia risk, the role of rare, small-sized variants at this locus-such as single nucleotide variants and short indels which are below the resolution of chip-based arrays requires further exploration. The aim of the present study was to investigate the association between rare TCF4 sequence variants and schizophrenia. Exon-targeted resequencing was performed in 190 German schizophrenia patients. Six rare variants at the coding exons and flanking sequences of the TCF4 gene were identified, including two missense variants and one splice site variant. These six variants were then pooled with nine additional rare variants identified in 379 European participants of the 1000 Genomes Project, and all 15 variants were genotyped in an independent German sample (n?=?1,808 patients; n?=?2,261 controls). These data were then analyzed using six statistical methods developed for the association analysis of rare variants. No significant association (P?TCF4 sequence variants in schizophrenia risk is warranted by the assessment of larger cohorts with higher statistical power to identify rare variant associations. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 51 | Neuron 2016 Apr 90: 43-55 |
| PMID | 26971948 |
| Title | Psychiatric Risk Gene Transcription Factor 4 Regulates Intrinsic Excitability of Prefrontal Neurons via Repression of SCN10a and KCNQ1. |
| Abstract | Transcription Factor 4 (TCF4) is a clinically pleiotropic gene associated with schizophrenia and Pitt-Hopkins syndrome (PTHS). To gain insight about the neurobiology of TCF4, we created an in vivo model of PTHS by suppressing TCF4 expression in rat prefrontal neurons immediately prior to neurogenesis. This cell-autonomous genetic insult attenuated neuronal spiking by increasing the afterhyperpolarization. At the molecular level, using a novel technique called iTRAP that combined in utero electroporation and translating ribosome affinity purification, we identified increased translation of two ion channel genes, Kcnq1 and Scn10a. These ion channel candidates were validated by pharmacological rescue and molecular phenocopy. Remarkably, similar excitability deficits were observed in prefrontal neurons from a TCF4(+/tr) mouse model of PTHS. Thus, we identify TCF4 as a regulator of neuronal intrinsic excitability in part by repression of Kcnq1 and Scn10a and suggest that this molecular function may underlie pathophysiology associated with neuropsychiatric disorders. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 52 | Cell Rep 2016 Apr 15: 386-97 |
| PMID | 27050508 |
| Title | Type I bHLH Proteins Daughterless and Tcf4 Restrict Neurite Branching and Synapse Formation by Repressing Neurexin in Postmitotic Neurons. |
| Abstract | Proneural proteins of the class I/II basic-helix-loop-helix (bHLH) family are highly conserved transcription factors. Class I bHLH proteins are expressed in a broad number of tissues during development, whereas class II bHLH protein expression is more tissue restricted. Our understanding of the function of class I/II bHLH transcription factors in both invertebrate and vertebrate neurobiology is largely focused on their function as regulators of neurogenesis. Here, we show that the class I bHLH proteins Daughterless and TCF4 are expressed in postmitotic neurons in Drosophila melanogaster and mice, respectively, where they function to restrict neurite branching and synapse formation. Our data indicate that Daughterless performs this function in part by restricting the expression of the cell adhesion molecule Neurexin. This suggests a role for these proteins outside of their established roles in neurogenesis. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 53 | Neuroscience 2016 Feb 314: 1-11 |
| PMID | 26628400 |
| Title | OSO paradigm--A rapid behavioral screening method for acute psychosocial stress reactivity in mice. |
| Abstract | Chronic psychosocial stress is an important environmental risk factor for the development of psychiatric diseases. However, studying the impact of chronic psychosocial stress in mice is time consuming and thus not optimally suited to 'screen' increasing numbers of genetically manipulated mouse models for psychiatric endophenotypes. Moreover, many studies focus on restraint stress, a strong physical stressor with limited relevance for psychiatric disorders. Here, we describe a simple and a rapid method based on the resident-intruder paradigm to examine acute effects of mild psychosocial stress in mice. The OSO paradigm (open field--social defeat--open field) compares behavioral consequences on locomotor activity, anxiety and curiosity before and after exposure to acute social defeat stress. We first evaluated OSO in male C57Bl/6 wildtype mice where a single episode of social defeat reduced locomotor activity, increased anxiety and diminished exploratory behavior. Subsequently, we applied the OSO paradigm to mouse models of two schizophrenia (SZ) risk genes. Transgenic mice with neuronal overexpression of Neuregulin-1 (Nrg1) type III showed increased risk-taking behavior after acute stress exposure suggesting that NRG1 dysfunction is associated with altered affective behavior. In contrast, TCF4 transgenic mice displayed a normal stress response which is in line with the postulated predominant contribution of TCF4 to cognitive deficits of SZ. In conclusion, the OSO paradigm allows for rapid screening of selected psychosocial stress-induced behavioral endophenotypes in mouse models of psychiatric diseases. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 54 | Transl Psychiatry 2016 -1 6: e724 |
| PMID | 26836412 |
| Title | Polymorphisms in MIR137HG and microRNA-137-regulated genes influence gray matter structure in schizophrenia. |
| Abstract | Evidence suggests that microRNA-137 (miR-137) is involved in the genetic basis of schizophrenia. Risk variants within the miR-137 host gene (MIR137HG) influence structural and functional brain-imaging measures, and miR-137 itself is predicted to regulate hundreds of genes. We evaluated the influence of a MIR137HG risk variant (rs1625579) in combination with variants in miR-137-regulated genes TCF4, PTGS2, MAPK1 and MAPK3 on gray matter concentration (GMC). These genes were selected based on our previous work assessing schizophrenia risk within possible miR-137-regulated gene sets using the same cohort of subjects. A genetic risk score (GRS) was determined based on genotypes of these four schizophrenia risk-associated genes in 221 Caucasian subjects (89 schizophrenia patients and 132 controls). The effects of the rs1625579 genotype with the GRS of miR-137-regulated genes in a three-way interaction with diagnosis on GMC patterns were assessed using a multivariate analysis. We found that schizophrenia subjects homozygous for the MIR137HG risk allele show significant decreases in occipital, parietal and temporal lobe GMC with increasing miR-137-regulated GRS, whereas those carrying the protective minor allele show significant increases in GMC with GRS. No correlations of GMC and GRS were found in control subjects. Variants within or upstream of genes regulated by miR-137 in combination with the MIR137HG risk variant may influence GMC in schizophrenia-related regions in patients. Given that the genes evaluated here are involved in protein kinase A signaling, dysregulation of this pathway through alterations in miR-137 biogenesis may underlie the gray matter loss seen in the disease. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 55 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2016 Apr -1: -1 |
| PMID | 27103199 |
| Title | Polymorphisms of the TCF4 gene are associated with the risk of schizophrenia in the Han Chinese. |
| Abstract | schizophrenia (SCZ) is a complex and severe mental disorder with highly heritability (80%). Several large genome-wide association studies have identified that the transcription factor 4 (TCF4) polymorphisms were strongly associated with SCZ. Therefore, the present study was to replicate the potential relationships between the TCF4 polymorphisms and SCZ. Furthermore, the study also investigated whether other variants were associated with SCZ in the Han Chinese. We conducted a case-control study including 499 patients and 500 healthy controls. Five SNPs were successfully genotyped and evaluated the association with SCZ by using ?(2) test and genetic model analysis. We found that the genotype "AG" of rs9320010 and "GA" of rs7235757 decreased SCZ risk (OR?=?0.70, 95%CI?=?0.50-0.99, P?=?0.041; OR?=?0.69, 95%CI?=?0.49-0.97, P?=?0.034, respectively). In the genetic model analysis, we also observed that the allele "A" of rs9320010 and "G" of rs7235757 were inversely related with the risk of SCZ in the dominant model (OR?=?0.72, 95%CI?=?0.52-0.98, P?=?0.039; OR?=?0.69, 95%CI?=?0.50-0.96, P?=?0.025, respectively). Further interaction and stratification analysis suggested that rs1452787 was notably correlated with increased SCZ risk in males (OR?=?2.77, 95%CI?=?1.43-5.35, P?=?0.002). Our study indicated that rs9320010, rs7235757, and rs1452787 were prominently associated with SCZ. Further studies are required to verify our findings and focus on determining the biological functions of the SNPs. © 2016 Wiley Periodicals, Inc. |
| SCZ Keywords | schizophrenia, schizophrenic |